• Title, Summary, Keyword: Spectral range

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Electroglottographic Spectral Tilt in Frequency Ranges of Vowel Sound (모음 주파수 범위에 따른 성문전도 스펙트럼 기울기)

  • Kim, Ji-Hye;Jang, Ae-Lan;Jung, Dong-Keun
    • Journal of Sensor Science and Technology
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    • v.24 no.4
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    • pp.247-251
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    • 2015
  • In this study, electroglottographic spectral tilt (EST) was investigated for characterization of vocal cords vibration. EST was analyzed from the power spectrum of electroglottographic signals by dividing frequency analysis range as full range (0~4 octave), low range (0~2 octave), and high range (2~4 octave). EST of all ranges in female were greater than those in male. In female and male groups, EST of high range was higher than that of low range. This result suggests that EST has at least two components and dividing frequency range in analysis of EST is effective for investigating characteristics of vocal cords vibration.

Control of Free Spectral Range of tong Period Fiber Grating by Cladding Mode Waveguide Dispersion

  • Jeong, H.;Oh, K.
    • Journal of the Optical Society of Korea
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    • v.7 no.2
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    • pp.89-96
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    • 2003
  • A new method to control the free spectral range of a long period fiber grating is proposed and theoretically analyzed. As the refractive index decreases radially outward in the silica cladding due to graded doping of fluorine, waveguide dispersion in the cladding modes was modified to result in the effective indices change and subsequently the phase matching conditions for coupling with the core mode in a long period fiber grating. Enlargement of the free spectral range in a long period fiber grating was theoretically confirmed.

Ternary Bulk Heterojunction for Wide Spectral Range Organic Photodetectors

  • Shin, Hojung;Kim, Jaehoon;Lee, Changhee
    • Journal of the Korean Physical Society
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    • v.71 no.4
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    • pp.196-202
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    • 2017
  • Ternary bulk heterojunction (BHJ) system, dual electron donors and an acceptor, was studied for developing wide spectral range organic photodetectors (OPDs). With two electron donor polymers with different bandgaps and an efficient electron acceptor of [6,6]-Phenyl-C71-butyric acid methyl ester ($PC_{70}BM$), different blend ratios for ternary BHJ OPD were examined to achieve high photoresponsivity over a wide spectral range. OPDs based on ternary BHJ showed improved photovoltage response compared to binary BHJ. Current-voltage (J-V) characteristics as a function of external bias and light illumination were measured to reveal the underlying charge recombination mechanism which is found to be dominantly ruled by space charge limit (SCL) effect. Additional in-depth analyses including absorbance, cross-section scanning electron microscope (SEM), incident photon-to-electron conversion efficiency (IPCE) were performed.

Measurement of Solar Cell Using LED-based Differential Spectral Responsivity Comparator under High Background Irradiance

  • Zaid, Ghufron;Park, Seong-Chong;Lee, Dong-Hoon;Park, Seung-Nam
    • Proceedings of the Optical Society of Korea Conference
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    • pp.293-294
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    • 2009
  • The spectral responsivity of solar cells has been measured under high background irradiance using an LED-based differential spectral responsivity Comparator (DSR-C). The comparator developed is fully automated and has some advantages: It does not need a chopper to modulate the light. Unlike the conventional method, it does not require a monochromator to select wavelength. It covers a wavelength range up to 1200 nm. The wavelength range of the comparator is limited by the spectral power distribution of the LEDs and the spectral responsivity of the standard detector. An active temperature control was utilized to meet the specified standard conditions of solar cell test. This work shows the effect of different levels of background irradiance on the spectral responsivity and the importance of same background irradiance for solar cell test as specified by the corresponding standard.

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Extension of the Dynamic Range in the CMOS Active Pixel Sensor Using a Stacked Photodiode and Feedback Structure

  • Jo, Sung-Hyun;Lee, Hee Ho;Bae, Myunghan;Lee, Minho;Kim, Ju-Yeong;Choi, Pyung;Shin, Jang-Kyoo
    • Journal of Sensor Science and Technology
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    • v.22 no.4
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    • pp.256-261
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    • 2013
  • This paper presents an extension of the dynamic range in a complementary metal-oxide-semiconductor (CMOS) active pixel sensor (APS) using a stacked photodiode and feedback structure. The proposed APS is composed of two additional MOSFETs and stacked P+/N-well/P-sub photodiodes as compared with a conventional APS. Using the proposed technique, the sensor can improve the spectral response and dynamic range. The spectral response is improved using an additional stacked P+/N-well photodiode, and the dynamic range is increased using the feedback structure. Although the size of the pixel is slightly larger than that of a conventional three-transistor APS, control of the dynamic range is much easier than that of the conventional methods using the feedback structure. The simulation and measurement results for the proposed APS demonstrate a wide dynamic range feature. The maximum dynamic range of the proposed sensor is greater than 103 dB. The designed circuit is fabricated by the $0.35-{\mu}m$ 2-poly 4-metal standard CMOS process, and its characteristics are evaluated.

Water Stress Reaction of Rice that see as Spectral Reflection Characteristics (분광반사특성으로 본 벼의 물 스트레스 반응)

  • Shin, Yong-Hee;Park, Jong-Hwa;Lee, Sang-Hyuk
    • Proceedings of the Korean Society of Agricultural Engineers Conference
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    • pp.513-516
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    • 2001
  • Water stress measurements of rice that use spectral reflection characteristics have been conducted to detect a water stress of rice during growing stage. Water stress reaction was measured using a spectroradiometer in the wavelength range from 300nm to 1100nm. In order to maintain all the experimental conditions, the measurement time have been settled at a fixed solar radiation times. Spectral reflectance were measured as a function of the moisture content. The results indicate that the spectral reflectance of rice was dependent on moisture content. As the moisture content is lowered the spectral reflectance of rice formed in NIR wavelength range increased. This effect can be best explained in terms of water stress.

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Near-IR Spectral Features of Haze Particles in the Atmosphere of Titan

  • Kim, Sang Joon
    • The Bulletin of The Korean Astronomical Society
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    • v.38 no.1
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    • pp.62.1-62.1
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    • 2013
  • The Cassini/Visual Infrared Mapping Spectrometer (VIMS) observed the sun through the atmosphere of Titan, and provided vertically-resolved 63 spectra from 49 km to 987 km for the 1 - 5 micron range (Bellucci, 2008). Bellucci et al. (2009) analyzed selected spectral ranges where the band absorptions of $CH_4$ and CO are strong by constructing synthetic spectra including $CH_4$ and CO lines, but without including haze absorptions in their synthetic spectra. Kim et al. (2011) and Sim et al. (2013) were able to extract detailed spectral features of fundamental (Dv = 1) and overtone (Dv = 2) bands of the haze from the VIMS spectra by excluding the adjacent influences of strong $CH_4$ absorptions using a radiative transfer program, which includes effects of absorption and emission of lines of these molecules, and absorption and scattering of haze particles. In this presentation, we extend our detailed analyses to other remaining wavelengths in order to provide the spectral characteristics of the Titanian haze for the entire 1 - 5 micron range and to identify any additional haze spectral features and an unidentified feature near 4.3 microns reported by Bellucci et al. (2009).

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Research on the Technology of Alternative Continuous Wide Spectral Spatial Heterodyne Spectrometer

  • Zhang, Wenli;Tian, Fengchun;Zhao, Zhenzhen;Song, An;Zhang, Li
    • Current Optics and Photonics
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    • v.1 no.4
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    • pp.295-307
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    • 2017
  • An innovative system for the alternative continuous wide spectral spatial heterodyne spectrometer (ACWS-SHS) is proposed. The relationship between the ACWS-SHS and the wide spectral spatial heterodyne spectrometer (WS-SHS) at the resolution limit, the spectral range, the grating diffraction efficiency and the interference fringes contrast ratio has been analyzed theoretically. Through the comparison of the theoretical analysis and simulation results, it is found that the two systems for the WS-SHS and the ACWS-SHS have the same resolution limit and spectral range, which are ${\delta}{\sigma}$ and ${\sigma}_{01}$, while in the ACWS-SHS system the critical diffraction efficiency of echelle grating is 68.39% and the critical contrast ratio of interference fringes is 0.4135, which is much better than the performance of the WS-SHS system. Therefore, the ACWS-SHS reduces the high requirements for the precision of equipment and expands the application field of SHS effectively.

Development of Spectral Irradiance Measurement System (분광복사조도 측정 장치 개발)

  • Seo, Jung-Chul
    • Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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    • v.18 no.5
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    • pp.48-53
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    • 2004
  • Spectral irradiance measurement system was developed to measure the spectral irradiance of optical sources in the wavelength range from 250[nm] to 1600[nm]. Our system is composed of source system, fore-optics, monochromator system, optical detector system, and automatic control system. Optical detector system with PMT, Si, InGaAs, and IR enhanced InGaAs detectors is used to measure the wide spectrum of optical sources in ultraviolet visible, and infrared wavelength regions. Spectral irradiance of the 1[kW] quartz-halogen tungsten lamp was measured and compared in the wavelength range from 250[nm] to 1600[nm]. The differences between our results and those reported by NIST are below 3[%], 3.5[%], and 5[%] in the wavelength range of 450∼700[nm], 700∼1600[nm], 250∼400[nm], respectively.